Electromagnetic ignition device,particularly for lighters



R. HALM May 13, 1969 ELECTROMAGNETIC IGNITION DEVICE, PARTICULARLY FORLIGHTERS Filed July 15, 1967 RICHARD HALM United States Patent OfficePatented May 13, 1969 Int. Cl. Fist 3/01 US. Cl. 317-81 12 ClaimsABSTRACT OF THE DISCLOSURE Electromagnetic ignition device with apermanent magnet in a magnet circuit, including a laminated U-shapedyoke provided with a low-tension winding and a hightension winding, intoone leg portion of which yoke a permanent magnet is inserted, the otherleg portion carrying the high and low tension windings. An armature ismovably arranged between the yoke leg portions. Pivoting of a liddownwards tensions a leaf-type spring finally to tear the armature fromabutment with the yoke. Fuel is emitted from a storage reservoir througha valve actuated by the pivoting of the lid. Following emission of fuel,the armature, in tearing off the yoke, breaks open the low tensionwinding to cause a spark to jump a gap in the high tension winding toignite the fuel.

CROSS REFERENCE TO RELATED APPLICATIONS This application is entitled tothe priority filing date of the corresponding German patent applicationNo. H 59,972, filed July 15, 1966.

This is a continuation in-part to copending patent application S.N.397,969, filed Sept. 21, 1964, and priority thereof is claimed for allsubject matter common therewith.

Field of the invention Broadly the present invention relates to a burnerhaving an electric spark igniter. Specifically, the present inventionrelates to an electromagnetic ignition device with a permanent magnet ina magnetic circuit.

' The magnetic circuit has a laminated yoke and a movable armature. Theyoke iss provided with a low-tension winding and a high-tension winding.The invention is concerned more particularly with a small lighter,especially a pocket lighter, comprising a fuel tank, a spark gapdisposed over a burner nozzle and operatively connected with thehigh-tension winding, and an actuating member for the armature of theignition device and the burner valve.

Description of the prior art The operation of electric spark ignitiondevices of the prior art include a tearing of an armature away from ayoke, whereby at least one air gap formed between the armature and theyoke is abruptly increased. As a result of the change of the magneticfiux in the magnetic circuit thereby produced, a corresponding voltagepulse is induced in a coil to supply, in a lighter, the ignition sparkfor a gas-air mixture at a burner nozzle.

During the opening of each magnetic circuit, a leakage fiux is producedwhich increases with the growing air gap and reduces the change of fluxwith the ultimate result that the induced voltage will not attain thevalue actually possible on the basis of the strength or power of thepermanent magnet which, in turn, depends upon the volume and magneticmaterial of the latter.

Because of this leakage flux and because of the relatrvely small contactsurfaces between the armature and the yoke, it has not been possibleheretofore to reduce the dimensions of the ignition device to an extentsuch as would be required, on the one hand, for a small lighter,particularly a pocket lighter, if, on the other hand, an ignition sparkof sufiicient power were to be produced with absolute certainty.

SUMMARY OF THE INVENTION It is, therefore, the object of the presentinvention to provide a small lighter while nevertheless being equippedwith an electromagnetic ignition device by proposing improvements forsuch devices of the prior art.

For the purpose of obtaining this object, the present invention uses asits basis an electromagnetic ignition device with a magnetic circuitcomprising a U-shaped yoke, one leg portion of which is provided wth apermanent magnet inserted therein and the other leg portion of whichcarries an induction winding, and an armature disposed between the legportions of the yoke in a movable fashion.

In accordance with the present invention, the pole shoe surface areas ofthe yoke and of the armature are made larger than the cross-sectionalsurface areas of the yoke leg carrying the induction winding, and thearmature is provided with a pole shoe which projects toward the poleshoe of this yoke leg.

An increase of the pole surface area of approximately 20% as compared tothe cross section of the yoke results already in a marked reduction ofthe magnetic contact or transition resistance within the air gap, andthis contact resistance obviously decreases in the same proportion asthe two pole surfaces increase with respect to the yoke cross section,all conditions being otherwise identical. The contact or transitionresistance is advantageously further reduced if the pole surfaces of thearmature and of the yoke are accurately machined and perfectly matchedwith regard to each other.

The pole shoe of the armature projecting toward the yoke pole shoeprevents the generation of a detrimental stray flux toward the armaturebody which would counteract the desirable temporary change of flux,which should be as great as possible, at the time when the armature istorn away from the yoke.

In order to prevent that the dimensions of the system be increased bythe pole shoe of the armature, a front plate of the induction windingfacing the armature is advantageously provided with a recess into whichthe armature pole shoe fits when abutting with the pole shoe of theyoke.

A particular problem arises with respect to the combination of thesheets of the yoke and of the armature to constitute compact stacks ofsheets. The customary provision of screws or rivets is not feasible heresince it reduces the magnetic cross section and thus makes an increaseof the cross sectional dimensions of the stack mandatory for a requiredvalue of magnetization, which increase counteracts the object ofcompactness to be Ohtained with the present invention. Furthermore,harmful short-circuit connections are produced as a result of the screwor rivet connection in which eddy currents are formed during changes offlux.

For this reason, it is a further characteristic of the present inventionthat, at points which are positioned at the outer circumference of themagnetic circuit, the sheets are connected with each other by means of afusion connection, for example by welding or soldering. The provision ofa fusion connection at the periphery of the magnetic circuit has theadvantage that the magnetic flux is considerably smaller there and isless disadvantageously influenced than it would be in the center of thecross section, for example.

A further problem arising when a small ignition device is to beconstructed concerns the mechanically rigid connection of yoke partswith respect to one another and the movable positioning of the armaturein a manner such that the strong power required for tearing off thearmature and the impacts which arise in catching or intercepting thearmature movement are absorbed without loosening the connection andwithout impairing the precise fitting of the armature onto the poles ofthe yoke and of the permanent magnet between the yoke parts.

In accordance with the present invention, the smallest possiblestructural form is obtained if, instead of a mounting on a pedestal oron a plate bar, the parts of the yoke are disposed at a supporting platewhich is provided as an angle section and made from non-magnetic butsuitably electrically-conductive material, the two leg portions of theangle section resting against two neighboring sides of the yoke.

An arm may advantageously be disposed on the supporting plate as anintegral part thereof within the area of the armature to carry anelastic contact member of an interterrupter contact. Such an interruptercontact is customary in this construction and is actuated by thearmature.

If, furthermore, a rigid counter contact of the inter-- rupter contact,for operative engagement with the elastic contact member, is disposeddirectly and in an insulated manner at the front plate of the inductionwinding adjacent the armature, a further saving in space is realized ascompared to an interrupter contact mounted at a separate insulatingmember.

Other objects and many of the attendant advantages of this inventionwill be readily appreciated as the same becomes better understood byreference to the following detailed description when considered inconnection with the accompanying drawings in which like referencenumerals designate like parts throughout the figures thereof.

An advantageous use of the available space, which use contributesessentially to reducing the structural bulk of the ignition device andtherewith that of the lighter iself, is realized addiionally in that theconventional condenser which is connected in parallel to the interruptercontact is accommodated in the free space of the yoke present betweenthe induction winding and the permanent magnet. This measure results inshort conductor connections between the condenser and the rigid countercontact of the interrupter contact on the front plate, on the one hand,and the supporting plate as mass connection of the electrical circuit,on the other hand.

BRIEF DESCRIPTION OF THE DRAWING A lighter as embodiment of the presentinvention is schematically illustrated in the accompanying drawing,wherein FIGURE 1 is a lateral view of the lighter of the presentinvention sectioned to disclose its interior;

FIGURE 2 is a top plan view of the lighter of the present inpention withits lid removed;

FIGURE 3 is a rear view of elements indicated in FIG- URE 1;

FIGURE 4 is a partial view in the direction of the arrow A in FIGURE 3with a modified part;

FIGURE 5 is a view corresponding to FIGURE 3 with the armature shownopen;

FIGURE 6 is a view corresponding to FIGURE 3 of a modification thereof;

FIGURE 7 is a circuit diagram applicable to the embodiments of thepreceeding figures.

DESCRIPTION OF THE PREFERRED EMBODIMENT Acconrmodated at the two endfaces of a two-piece housing 1, 1' of non-magnetic material are twostorage reservoirs 2 and 3 for fuel gas. These storage reservoirs are .4connected with each other by means of a connecting line 4. The upperside of the housing is covered with a lid 5 of non-magnetic materialwhich is pivotally positioned above the reservoir 2 by means of a crosspin 6 extending through the housing. The lid 5 has on the side thereofadjacent the cross pin 6 air passages 7 and thereabove a fire hole 43,and has on the side thereof adjacent the reservoir 3 an opening 8 asaccess to a charging port 9 within the reservoir 3. The housing shell 1is intended to be secured by means of screws to the housing shell 1'receiving the reservoirs 2, 3, and these screws must be threaded intapped holes 10 disposed at the reservoirs 2 and 3. The housing may becovered at the outside thereof with a leather-like plastic or the like.

Disposed above the reservoir 2 is an insulating member 13 of ceramicmaterial containing electrodes 11 and 12. It is secured to the housingpart 1' by means of a screw 14. Positioned on the screw 14 is at thesame time an actuating lever 15 for a gas valve 16 provided as a burner.The lever is accommodated within a slot of the insulating member 13. Theelectrodes 11, 12 are provided with platinum tips so as to effectivelyprevent the oxidation of the tips.

A permanent magnet 21 is inserted between two yoke members 22 and 23which consist of mutually insulated layers of sheets and are heldtogether at the outer sidereferred to the magnetic circuit-by means oftransverse soldered seams 24. Through the yoke member 22 extends a pivot25 as bearing for a rocking lever 26 which encloses, at the end thereofthrough which the pivot 25 extends, the yoke member 22 and whichreceives at the end thereof removed from the pivot 25 an armature 27,which latter is best seen in FIGURE 5. The armature is constructed inthe manner of the yoke members 22, 23 and has a pole shoe 28 projectingabruptly from its body. The leg portion 51 of the yoke 23 provided withinduction winding 29 has a pole shoe 30 which corresponds to the poleshoe 28. Pole shoes 28 and 30 have the same cross section. Both poleshoes are accurately machined and ground on their mutually abuttingsurfaces which are shown flush with respect to each other in theposition illustrated in FIGURE 3 and separated in the positionillustrated in FIGURE 5.

The pole shoe 30 has a square-shaped cross section which is larger inarea than the cross section of the cylindrical leg portion 51. Thediameter of the cylindrical leg portion 51 may correspond approximatelyto the length of the side of the square of pole shoe 30, as shown inFIGURE 4. Winding space is gained by virtue of the cylindricalconfiguration of the yoke leg portion. Addi tional space may be saved ifonly a thin insulating layer of paper is inserted between leg portion 51and the winding 29. The front plate 36 of the winding is disposedradially outwardly of the pole shoe 30 and is held at its socket-likepart by means of a lateral blasting off or separation of material of theyoke leg portion 51. The other front plate 50 is flat and is simply slidupon the leg portion 51 flush against the winding.

Secured to the end face of the rocking lever 26 is a leaftype spring 42which rests with the free end thereof from below against the inner sideof the lid 5.

The yoke members 22 and 23 are connected by means of soldering with asupporting plate 31 of a conducting but non-magnetic material. Thesupporting plate is angularly bent to rest against two adjacent surfacesof the yoke members; and is thereby reinforced (FIGURE 3). The permanentmagnet 21 is pressed in between the oppositely directed leg portions ofthe two yoke members (FIGURE 1). The supporting plate 31 is secured tothe housing shell 1' by means of screws which engage in tapped holes 41in the supporting plate, these holes being disposed in the dead spacebetween the two yoke leg portions not utilized by the induction winding29 (FIG- URE 3).

Accommodated in this space is furthermore a condenser 38 in aspace-saving manner.

An arm 32 integral with the supporting plate 31 carries a breaker spring33 having a contact 34 at the free end thereof. This contact 34 is shownin FIGURE 3 in operative engagement with a counter contact 35 disposedin an insulated manner on the front plate 36 of the coil. This countercontact is connected by way of a line 37 with one terminal of thecondenser 38 whose other terminal is connected with the supporting plate31 by way of a line 39.

The interrupter switch comprising contacts 34 and 35 and the condenser38 are connected in parallel with respect to the low-tension winding ofthe induction winding 29. The housing shells 1 and 1 and the supportingplate 31 form the chassis as it were of the electrical circuit. A line39 extends from the high-tension winding of the induction winding to theelectrode 12, while the electrode 11 is connected with the housing 1.

In the embodiment according to FIGURE 6, the armature 27' is angularlybent with respect to pole shoe 28' having a cross section enlargedrelative to that of leg portion 51. To pole shoe 28' corresponds anenlarged pole shoe 30' which is arranged offset on one side to the legportion 51 of yoke member 23. The stray or leakage flux is reduced alsoby virtue of this construction.

For purposes of operating the lighter, the lid 5 is pivoted about thecross pin 6 in the direction toward the reservoir 3 by means of pressureexerted at the end containing the access opening 8 whereby the spring 42is tightened and ultimately tears the armature 27 secured within therocking lever 26 away from the yoke leg portion 23. At the same time,the actuating lever is pressed down by the lid 5 and opens the gas valve16 so that an ignitable gas mixture is present when during thetearingotf movement the lever 26 lifts the contact 34 disposed on theend of breaker spring 33 off the counter contact 35 so that as a resultan ignition spark will jump between the electrodes 11 and 12. The flamewill emerge from the fire hole 43 in the lid 5.

When the lid 5 is released, the armature 27 will return into theposition illustrated in FIGURES 1 and 3 due to the magnetic attractionbetween the pole shoes. The spring 42 presses the cover or lid upwardlyagain and is relaxed, the actuating lever 15 is released and the gasvalve 16 closes automatically by means of a valve spring installed as isknown in connection with gas lighters, whereafter a new tearing-offprocess may be initiated.

The pocket lighter described herein is approximately 65 mm. long, has aheight of 40 mm. and a width of approximately 10 mm. at the end facesand of approximately 18 mm. within the area of the coil 29. The distancebetween the two storage reservoirs 2, 3 is approximately 44 mm. Thepocket lighter has been shown in the drawing enlarged about 1.5 times.

The small-construction ignition device proposed by the present inventionis, however, by no means restricted to pocket lighters in the usethereof but may be used advantageously also in any case whereelectromagnetic devices operable without battery or without power supplyare needed for generating a strong high-tension impulse, for example forigniting oil or gas burners, mines, and the like.

It should be understood, of course, that the fore-going disclosurerelates to only preferred embodiments of the invention and that it isintended to cover all changes and modifications of the examples of theinvention herein chosen for the purposes of the disclosure, which do notconstitute departures from the spirit and scope of the invention setforth in the appended claims.

I claim:

1. An electric spark igniter for small lighters and similar devices,comprising a magnetic circuit means to conduct a magnetic flux; saidmagnetic circuit means including a permanent magnet (21) and, in series,a leg portion (51), a pole shoe (30), a pole shoe (28), and an armature(27); pole shoes (28) and (30) connected respectively to the armature(27) and the leg portion (51), the pole shoe (28) projecting from thearmature (27); means to actuate said armature (27) to move said poleshoe (28) into and out of abutment with said pole shoe (30) and toeffect a change in the magnetic flux conducted in the magnetic circuitmeans; and electrical circuit means to utilize said change in magneticflux to create a spark, the electrical circuit means including a winding(29) wound on said leg portion (51), and electrode means (11, 12)connected to said winding (29) to provide a spark gap, one end of thewinding (29) lying substantially coplanar with the abutment between poleshoes (28) and (30); leg portion (51), pole shoes (28) and (30) inabutment, and winding (29) being coaxial, the armature (27) extendingsubstantially perpendicularly to their axis; the cross sections of thepole shoes (28) and (30) being greater than the cross section of legportion (51), and a housing for assembling the elements of the electricsparkigniter.

2. An electric spark igniter according to claim 1, further comprising afront plate (36) of the induction winding mounted on said leg portion(51) and facing the armature and provided with a recess, said pole shoe(28) mating with said recess when in abutment with pole shoe (30).

3. An electric spark igniter according to claim 1, wherein said magneticcircuit means includes a U-shaped yoke, one leg portion of which isprovided with said permanent magnet (21), the other leg portion of whichis said leg portion (51), the igniter further comprising a condenser(38) positioned between the said two leg portions.

4. An electric spark igniter according to claim 1, said winding (29)provided with high tension and low tension windings, said electrodemeans (11, 12) connected to said high tension winding; said means toactuate and to effect a change comprising a lid (5), means to mount thelid (5) pivotally, means to mount the armature (27 pivotally, a springmeans (42) acting between the lid (5) and the armature (27 to tear poleshoe (28) from pole shoe (30) upon achievement of a minimum spring forcecreated by pivoting of the lid (5), an interrupter switch in said lowtension winding, means to mount said switch in the path of motion ofsaid armature, whereby the switch is broken by impingement of saidarmature moving said pole (28) out of abutment with the pole shoe (30);the igniter further comprising a means operable by movement of said lid(5) to supply a fiow of ignitable fuel before the breaking of theinterrupter switch of the low tension winding, and means to mix oxygenwith said fuel flow; said electrical circuit means including a spark gaplocated in said high tension winding and in the flow of fuel followingits oxygenation, sparking occurring upon the breaking of the switch ofthe low tension winding.

5. An electric spark igniter as claimed in claim 1 comprising a housingmeans (1, 1') to mount the magnetic circuit means, the means to actuateand to effect a change, and the electrical circuit means as a unit.

6. An electric spark igniter according to claim 1, the parts of saidmagnetic circuit means being mounted on a supporting plate (31) of anon-magnetic material, said plate having the shape of an angle section,the two leg portions of the angle section resting against two adjacentsides of the magnetic circuit means.

7. An electric spark igniter according to claim 6, the parts of saidmagnetic circuit outside of said permanent magnet (21) being formed oflayers of sheets, the sheets bein connected at the outer periphery ofthe said magnetic circuit with each other.

8. An electric spark igniter according to claim 7, the sheets beingconnected together by fusion connections (24), the supporting plate (31)being fusion connected to the magnetic circuit means.

9. An electric spark igniter as claimed in claim 6, said supportingmeans (31) to mount the magnetic circuit 7 means, the means to actuateand to effect a change, and the electrical circuit means as a unit.

10. An electric spark igniter according to claim 6, further comprisingan arm (32) within the area of the armature (27), said arm carrying anelastic contact member (33, 34) of an interrupter switch, said armmounted to said supporting plate (31) as an integral part thereof.

11. An electric spark igniter according to claim 10, further comprising:a front plate (36) mounted on the armature-facing end of the inductionwinding, a stationary counter contact (35) mounted insulatedly on thearmature-facing end of the inducting Winding (29) for operativeengagement with said elastic contact member (33, 34).

12. An electric spark igniter as claimed in claim 10, furthercomprising: a front plate (36) arranged on the armature-facing side ofthe winding (29) and mounted on the leg portion (51).

8 References Cited UNITED STATES PATENTS 2,427,719 9/1947 EXner 335 X2,536,468 1/1951 Russell 31792 3,246,207 4/1966 Remy 317-81 FOREIGNPATENTS 734,080 5/ 1966 Canada. 964,409 l/ 1950 France. 965,121 6/1957Germany.

VOLODYMYR Y. MAYEWSKY, Primary Examiner.

US. Cl. X.R.

